Variation of Force Applied During External Version With Different Patients’ Characteristic and Outcome of Version

Abstract

ABSTRACT

The morbidity and perinatal deaths associated with vaginal breech delivery have prompted an alternative approach: external cephalic version (ECV). Although ECV is safe and cost-effective, many clinicians and patients avoid the procedure because of fear of complications as well as a lack of experience. In this prospective observational study, the pressure applied during ECV was quantified using gloves that incorporate ultrathin pressure-force sensors. Participants were 92 women presenting at or after 36 weeks gestation with breech presentation, all of whom lacked contraindications to ECV. The degree of force applied for each attempt at version, or pressure–time integral (PTI-A), was estimated in relation to numerous patient-related and ultrasound factors.

ECV succeeded in nearly three fourths (73%) of women entered into the study. The number of attempts at version for each patient ranged from one to 6. The sum of pressure–time integral of all attempts at version (PTI-ECV) was lowest in women having a single attempt. Those having 2 attempts had PTI-ECV figures that were twice those of the single-attempt group, and values were highest for women having 3 or more attempts. No significant differences were noted among women having 3 to 6 attempts at version. The median PTI-A of successful attempts in women who completed version after one or 2 attempts was significantly lower than that for women who needed 3 or more attempts for version to succeed. For individual women, there was no difference in PTI-A between the successful attempt and the preceding failed attempt. This suggests that failures may reflect inefficient application of force rather than insufficient force. The only clinical variable that correlated significantly with the degree of applied force was uterine tone; a more tense uterus was associated with greater applied force. The 2 operators who attempted version in these cases applied comparable degrees of force.

The degree of force required for successful ECV in this study was quite variable. The investigators believe that failed version most often results not from inadequate force, but from less-than-efficient force application and that greater emphasis on ECV skill may improve the results.